1. Field of the Invention
The present invention relates to fuel injectors utilized in an internal combustion engines and more particularly, to fuel injectors which can reduce valve noise during the operation.
2. Description of the Related Art
An example of a known fuel injector for an internal combustion engine is disclosed in Japanese Laid-Open Patent Publication No. 2000-240525 and is reproduced in FIG. 2. FIG. 2 shows a sectional view of a fuel injector 7 for an internal combustion engine. The fuel injector 7 is designed to lift an armature, which forms a valve 6, by excitation of a coil and exhaust (inject) fuel through a jet opening 5a. Further, the fuel injector 7 has a jet opening downstream channel 5b that extends downstream from the jet opening 5a through a valve seat 5. The fuel injector 7 is configured such that fuel exhausted from the jet opening 5a can be diffused as much as possible into the engine and atomized.
However, because the jet opening downstream channel 5b is provided within the valve seat 5, the wall thickness B of the valve seat 5 on the downstream side of the jet opening 5a becomes relatively small. Therefore, noise which is caused by contact of the valve 6 with the valve seat 5 is transmitted through the thin portion of the valve seat 5 on the downstream side of the jet opening 5a and leaks to the outside of the fuel injector 7.